* claim: #1209
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011YdMi9BDdjWZ8twfeBHAXz
* Prism boolean: a curved edge at one level crosses the walls there only (#1209)
The prism boolean sews its result slab by slab and keeps, for each section segment, the operand
wall it was read beside; its history is built from those tags. `Stations::new` took every curved
edge between two walls as crossing them at every level, so where two pieces of one cylinder are
stacked (an arm's round end under a boss of that radius) the circle between them cleared the
wall tags of every slab. `prism_lineage::sewn` then gave up, the join or cut came out with no
history, and every face of the body was named from geometry (`exact: false`).
A curve whose control points lie at one level (a B-spline, or a NURBS curve with positive
weights, which lies in their convex hull) is at that level: it crosses the walls there only.
Any other curve still spans every level.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011YdMi9BDdjWZ8twfeBHAXz
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: bherbruck <brennen.herbruck@gmail.com>
